Improvement in piston-valves



UNITED STATES PATENT OFFICE..

M. P. MACK, OF OANANDAIGUA, NEW YORK.

Speciication forming part of Letters Patent N o. 53,3] 1, dated March 20, 1866.

To all whom it may concern:

Be it known that I, M. P. MACK, ot' Oan andaigua, in the county of Ontario and State of New York, have invented a new and Improved Steam-Valve; and I do hereby declare that the following is a full, clear, and exact description thereof, which will enable others skilled in the art to make and use the same, reference being had to theaccom pan ying drawings, forming a part of this specification, in which- Figure l represents a longitudinal central section of this invention. Fig. 2 is a transverse section of the same.

Similar letters ot' reference indicate like parts.

This invention relates to a steam -valve which is composed ot' a tubular double piston fitted into a tubular chamber, from which two channels lead one to each end of the steamcylinder. These channels are protected by bridges to prevent the pistons from catching' in the same, and the steam is supplied through a pipe leading into the valve-chamber near one end, and it passes through the tubular valve to reach the opposite end of the cylinder. The exhaust-pipe emanates from the middle ot' the valve-chamber, and the steam from either endofthe cylinder exhausts through the annular space left in the valve-chamber between the two pistons or heads ot the valve in such a manner that a valve is obtained which is perfectly balanced, and which works with comparatively little friction or loss of power.

A represents the steam-cylinder, into which is fitted the piston B of any suitable construction. Steam is admitted alternately to the opposite ends ot' said cylinder through the ports a a', which lead to the valve-chamber C, as shown in Fig. l of the drawings. This valve-chamber is bored out to receive the heads b b of the tubular double piston-valve D, and it is provided with two seats, c c', perforated with openings which lead to annular recesses in the valve-chamber, said recesses being made to communicate with the ports a a.

The openings in the seats are protected by bridges to prevent the heads b b from catching in the same, and the seats c c may be so arranged that they can be withdrawn from the valve-chamber and renewed whenever it may be desirable.

An annular space, d, is left between the two heads b b ot' the valve and the inner wall ot the valve-chamber, and through this annular space the steam which exhausts from the cylinder A reaches the exhaust-pipe E. F is the steam-supply pipe.

The operation is as follows: ln the position shown in Fig. l the valve admits steam to the cylinder through the port a and the steam eXansts through theporta. The steam, rushing in through the steam-pipe F, passes through the tubular valve D, so that the pressure on both ends of said valve is perfectly balanced.

NVhen the valve changes so that the head b comes above the port a., or between said port and the steam-pipe, the steam passes trom the steanlpipe through the tubular valve and through the port a in the cylinder, and the exhaust ta-kes place through the porta', annular space d, and pipe E. In either case the valve tloats in the steam, and it takes no more power to move the same undera head of steam ot' a hundred or more pounds to the square inch than it does in the open atmosphere.

By the bridges which cover the openings in the seats the valve is prevented to catch, and it requires but little attention to keep the pistons or heads of'the valves tight.

What I claim as new, and desire to secure by Letters Patent, is

The tubular valve D, with two heads, b b', in combination with the seats e c in the valvechamber ports a a', leading to the cylinder A, and with the steam and exhaust pipe, all constructed and operating substantially as and for the purpose described.

M. P. MACK.

Witnesses:

J. H. METGALF, CHARLES JONES. 

